As a small girl growing up in California, Laura Miller did not just long to visit Narnia. So bewitched was she by that imagined realm -- laid out in seven novels back in the 1950s by an eccentric English don -- she was pretty sure that not being able to visit it in person would kill her. Along with its various sequels and prequels, The Lion, the Witch and the Wardrobe brought her the purest sort of bliss. It was the book, she writes in this meandering but beguiling appreciation, "that made a reader out of me."

When Miller was in her early teens, she discovered "what is instantly obvious to any adult reader: that the Chronicles of Narnia are filled with Christian symbolism" and that the books that had been the cornerstone of her imaginative life were "really just the doctrines of the Church in disguise."

Miller had been raised a Catholic (close enough, for literary purposes, to C.S. Lewis's born-again Anglicanism), but she was left as cold as a Narnia winter by what she describes as the church's "guilt-mongering and tedious rituals." The sense of betrayal by Lewis was so great that for a long time she wanted nothing to do with his now "appallingly transfigured" fairy tale.

A lot of readers have felt that way about Narnia -- and not just since Disney's unsubtle blockbuster movie in 2005 left the whole series more or less hijacked by Christian fundamentalists. Lewis's longtime friend J.R.R. Tolkien, the creator of Middle-earth and a self-described "devout Roman Catholic," objected to what he considered the books' heavy-handed Christian parallels, too.

But Miller wasn't one to let disenchantment lie. Now a journalist and critic, she re-read The Lion, the Witch and the Wardrobe for an assignment a few years back and found that it had not entirely lost its radiance, its uncanny power to stir. "What I dislike about Narnia," she discovered, "no longer eclipses what I love about it." She set out to determine why -- and perhaps to help reclaim it for those misguidedly convinced that it is only a work of Christian apologetics.

The result is this hard-to-categorize, absorbing book. Think of it as an extended literary appreciation shot through with illuminating shafts of memoir, scholarship, biography and conversational interviews. Reading it is like sitting down for the afternoon with a fellow Narnia nut who is much more erudite than you are but genial and amusing enough never to intimidate or bore.

Well, almost never. But don't worry. Whenever a foray into medieval romance or a disquisition on mythopoeia starts to flag, you can just skip ahead -- and there will be Miller dissing Middle-earth as "the biggest model-railroad setup of all time," or tramping about Northern Ireland and Oxford looking for the real landscapes that inspired Narnia, or sharing Narnia-related confidences from the likes of Philip Pullman and Neil Gaiman. It's that kind of comfortable book.

You may find yourself thinking that Miller goes off on too many tangents. In fact, it takes a nimble mind to follow her through these 27 dense, often obliquely titled chapters ("Garlic and Onions," anyone? "Boxcar Children"?). But it finally becomes clear that her branching meditation only mirrors what she sees as the essence of the Narnia books, as well as the quality Tolkien most disliked about them: their joyous, magpie-like borrowing and blending.

"The Chronicles are unified," she writes, "not by anything resembling the exhaustive cultural stuff that Tolkien invented for Middle-earth . . . not even, really, by a cogent religious vision, but by readerly desire. Lewis poured into his imaginary world everything that he had adored in the books he read as a child and in the handful of children's books he'd enjoyed as an adult. And there is more, too: treasures collected from Dante, from Spenser, from Malory, from Austen, from old romances and ballads and fairy tales and pagan epics."

"The Chronicles," Miller concludes, "are a portal to other worlds, literary worlds."

Stick with her. As she methodically explores these rich "worlds," Miller largely succeeds in rescuing the Narnia series from the narrow Christian box into which it has been crammed and reminding us of its elemental power as a story, more resonant than any sermon, intended or otherwise. ·

Elizabeth Ward is an editor on the Post's foreign desk and a longtime reviewer of children's books.